broadcast address
Networking
A network's last address, host bits all set: a packet sent there is delivered to every host on the network at once. ip -o -4 addr show prints it as brd, derived from the prefix by the kernel, which checks your arithmetic for free. It can go to no machine, any more than the network's first address can, which names the network itself: hence 2ⁿ − 2 usable hosts, and 254 on a /24. DHCP uses it at start-up, when a client with no address addresses 255.255.255.255 for want of anyone to aim at.
Also written: brd, broadcast